Electrode for arc welding in air

ABSTRACT

An electrode for electric arc welding in air containing alkali metal composites which comprise an alkali metal oxide in combination with one or more metal compounds of acidic or amphoteric nature, preferably iron oxide, manganese oxide, aluminum oxide or silicon dioxide. The alkali metal composite is less hygroscopic than the alkali metal compound it contains and is capable of being reduced to elemental alkali metal in the welding arc by reducing agents contained in the electrode. The alkali metal composite is provided in sufficient quantity so that the alkali metal obtained therefrom reduces the nitrogen content of the weld metal sufficiently to suppress nitrogen boil in the weld metal. Certain metal oxides and fluorides, preferably oxides of silicon, calcium, or aluminum and fluorides of calcium, barium, lithium or sodium are moisture barrier materials and may be included in the alkali metal composite to further enhance its resistance to absorption of moisture from the air.

United States Patent 1 1 Haverstraw et a1.

[ ELECTRODE FOR ARC WELDING 1N AIR [75] Inventors: Robert Clairellaverstraw, Kirtland; George Gideon Landis, Pepper Pike Village, bothof Ohio [73] Assignee: The Lincoln Electric Company,

Cleveland, Ohio [22] Filed: May 7, 1971 [21] Appl. No.: 141,376

3,643,061 2/1972 Duttera 219/146 3,466,417 9/1969 Chapman et a1 219/1463,162,751 12/1964 Robbins 219/137 3,513,289 5/1970 Blake 219/1463,627,574 12/1971 Delong..... 117/206 3,585,352 6/1971 Zvanut 219/1463,461,270 8/1969 Patton 219/146 2,909,778 10/1959 Landis et a1. 219/1461 Oct. 23, 1973 3,531,620 9/1970 Arikawa et a1. 219/146 PrimaryExaminer-R. F. Staubly Assistant Examiner-George A. MontanyeAttorney-Meyer, Tilberry & Body [57] ABSTRACT An electrode for electricarc welding in air containing alkali metal composites which comprise analkali metal oxide in combination with one or more metal compounds ofacidic or ainphoteric nature, preferably iron oxide, manganese oxide,aluminum oxide or silicon dioxide. The alkali metal composite is lesshygroscopic than the alkali metal compound it contains and is capable ofbeing reduced to elemental alkali metal in the welding are by reducingagents contained in the electrode. The alkali metal composite isprovided in sufficient quantity so that the alkali metal obtainedtherefrom reduces the nitrogen content of the weld metal sufficiently tosuppress nitrogen boil in the weld metal. Certain metal oxides andfluorides, preferably oxides of silicon, calcium, or aluminum andfluorides of calcium, barium, lithium or sodium are moisture barriermaterials and may be included in the alkali metal composite to furtherenhance its resistance to absorption of moisture from the air.

41 Claims, No Drawings 1 ELECTRGDE FOR ARC WELDING IN AIR This inventionpertains to the art of electric arc welding and more particularly to an.improved electrode and method for electric arc welding in air.

The invention is particularly applicable to electric arc welding in airusing a bare tubular electrode wherein flux material is on the inside ofthe tube, and will be described with particular reference thereto,although it will be appreciated that the invention has in some instancesbroader application.

In the art of arc welding, a rod or tube-shaped electrode of weld metalis energized by an electric power source and an electric arc is struckbetween the electrode and the workpiece. The heat of the arc melts theelectrode and a spot on the workpiece into which the molten metal of theelectrode is deposited. It is, generally speaking, desired to deposit aweld metal which is free of porosity and which has a high impactstrength as well as satisfactory yield, tensile and elongationcharacteristics. The composition of the weld metal formed by theelectrode must be carefully controlled to assure that the weld has thesecharacteristics.

Porosity of the weld metal can be caused by various factors.

One cause of porosity is the reduction of' iron oxide to iron by carbonpresent in the workpiece metal, thereby causing carbon monoxide and/ordioxide gas to form in the molten weld metal and to be entrapped as themetal solidifies. A principal source of iron oxide is the reaction ofatmospheric oxygen with the molten surface of the weld bead and with thedroplets of the molten electrode as they move through the arc.

Accordingly, it has been known to provide in the electrode compositioncomponents known as deoxidizers, or reducing agents, which, because oftheir affinity for oxygen, would be oxidized in preference to the moltenweld metal, thus precluding the formation of iron oxide. Many materials,for example, aluminum, titanium, and silicon, to name but a few, areuseful as reducing agents but tend to alloy with the weld metal and ifpresent in excessive amounts to give it undesirable physicalcharacteristics such as brittleness, i.e., low impact strength.Magnesium and calcium are also good reducing agents, but have such lowboiling temperatures as to be less effective, and calcium is unstable inmoist air.

Another, and a major cause of porosity, is the entry into the weld poolof atmospheric nitrogen which dissolves in the molten weld metal. Thedissolved nitrogen gas seeks to come out of solution as the molten metalcools. The cooling metal solidifies around the escaping bubbles of gas,causing porosity of the metal. This phenomenon may be referred to asnitrogen boil. It is known that the nitrogen boil may be suppressed bythe use of excessive (over that required by deoxidization) reducingagents, such as aluminum, titanium and/or zirconium in the electrodecomposition. These excessive reducing agents react with nitrogen to formstable nitrides which are entrapped as an inclusion in the weld metal.Excessive amounts of these nitrides cause the resultant weld metal tohave poor impact properties. Unreacted, excess aluminum also enters theweld metal and, in excessive amounts (generally, anything in excess ofabout 1 percent aluminum), also has an adverse effect on themetallurgical properties of the weld metal, as hereinabove mentioned.

Consideration of those problems led to the conclusion that what wasneeded was a way to exclude nitrogen from the arc plasma and weld zone,thereby preventing it from entering the weld metal, rather than only toattempt to remove it after it has already entered. Accordingly, U.S.Pat. No. 2,909,648, dated Oct. 20, 1969, in the name of Landis et al.and assigned to the assignee of this application, describes the use of ametallic coating on the surface of a steel electrode which coatingvaporizes in the heat of the arc to provide a metallic vapor shieldaround the arc, thereby excluding the atmosphere (and its nitrogen) fromthe vicinity of the weld pool. Subsequent work indicated that lithiummetal was one of the best shielding metals and accordingly, copendingpatent application Ser. No. 2643, filed Jan. 13, 1970, now U.S. Pat. No.3,691,340 in the name of 6.6. Landis et al. and assigned to the assigneeof this application, discloses the use of lithium metal as an arcshielding material to protect the welding are by excluding theatmosphere therefrom. The lithium was believed to form a vapor shieldaround the droplets of the weld metal as they move from the are into theweld pool. Regardless of the mechanism involved, it is known thatintroducing elemental lithium into the welding arc suppresses thenitrogen boil without adversely affecting the metallurgical propertiesof the weld metal. Lithium boils at a temperature lower than the meltingpoint of steel and accordingly is boiled off so that it leaves noresidue in the weld metal.

In addition, other problems of a manufacturing nature which applicationSer. No. 2643 purports to solve, are involved in the application ofmetallic lithium to an electrode. The use of bonding and modifier metalsin conjunction with the lithium is required, as well as cleaning andshielding the electrode from the atmosphere during the coatingoperation.

U.S. Pat. No. 3,488,469, dated Jan. 6, 1970, in the name of R. C. Bussand assigned to the assignee of this application, describes a tubularelectrode containing, in addition to aluminum reducing agent andalloying agents, lithium carbonate. If lithium carbonate was introducedinto the arc in sufficient quantities, the nitrogen boil was suppressedwithout the need for introducing a nitride forming material (such asaluminum) in amounts which would unduly affect the impact strength ofthe weld metal, and a non-porous, good impact strength weld metal wasobtained.

Lithium carbonate however, is inefficient in that relatively largequantities of it are required in the formulation to suppress thenitrogen boil to the extent required to obtain a non-porous weld metal.

Further, the lithium carbonate employed by Buss decomposes to yieldcarbon dioxide gas in an explosive manner and in quantities which, whenthe lithium carbonate is present in amounts sufficient to suppress thenitrogen boil to the extent required to obtain substantially non-porousweld metal and satisfactory metallurgical properties, causes a spatterof molten weld metal. The spatter tends to disturb the operator, isunsightly, and has to be cleaned up after the welding operation iscompleted. Also, the release of carbon dioxide gas in such quantitiestends to disrupt the welding arc.

Although the Buss patent indicates that it was not known precisely howthe lithium carbonate functions, it implies that the excellent meltingaction of lithium carbonate and the closeness of its decompositiontemperature (1310 C.) to the melting point of steel provides shieldingof the weld metal from the atmosphere and its nitrogen.

Research carried out subsequent to the filing of the application whichultimately matured into the Buss patent noted that the compositiondescribed in the patent contained sufficient aluminum to reduce thelithium carbonate to elemental lithium in the heat of the arc, and thatthe satisfactory results obtained by Buss could be attributed to thepresence of the elemental lithium.

Accordingly, further work was carried out to test this theory and todetermine if other lithium compounds might serve as a source ofelemental lithium in the welding arc. The results of this research aredescribed in copending patent application Ser. No. 141,375, filed May 7,1971 (Method and Means for Electrode Welding) in the name of 1. Parksand assigned to the assignee of this application. In the Parksapplication, lithium compounds, preferably bimetallic lithium silicates,lithium fluoride or lithium silicates are combined in the electrode withreducing agents which reduce the compounds to elemental lithium in theheat of the welding arc. Although the lithium silicates can be reducedby magnesium, aluminum or silicon, lithium fluoride, the preferredlithium compound, requires calcium as a reducing agent. Calcium isreactive with the moisture in the air and accordingly, according to theParks application, is prepared in the form of air and storage-stableintermetallic compounds or alloyw with aluminum and magnesium.

-While the use of such reducing agents served to reduce lithium fluorideto elemental lithium in the amounts required, it was found that in orderthat these calcium-containing reducing agents be capable of being safelystored and handled during the manufacturing operation, they had to beblended to extremely precise formulations. Even minor variations fromthe prescribed formulations created materials which were difficult oreven dangerous to store and handle and which caused deterioration of theelectrode in storage because of the highly reactive nature of elementalcalcium with air and moisture. This very practical disadvantage ofelemental calcium reducing agents, i.e., the exacting manufacturingspecifications which must be met to provide a usable compound, indicatedthe need for non-hygroscopic lithium compounds which are capable ofbeing reduced to elemental lithium in the heat of the welding arewithout requiring the use of elemental calcium-containing reducingagents.

In order to meet the objective of developing lithiumcontaining materialswhich were stable in air for manufacturing and storage purposes andwhich could be reduced to elemental lithium in the welding arc withoutdecomposing into gaseous constitutents such as carbon dioxide'in amountswhich would disrupt the arc, it was reasoned that because they arestrongly basic, lithium compounds would combine readily with metalcompounds of an acidic or amphoteric nature to form compounds ormineral-like complexes. These compounds or complexes might be capable ofbeing reduced to elemental lithium in the welding arc without requiringcalcium reducing agents and without disruptive decomposition, and yet besufficiently stable and not so hygroscopic as to preclude their use in awelding electrode.

The metal of the acid or amphoteric compound selected would also have tohave desirable metallurgical properties in the proportions in which itwould enter the weld metal, because the strong reducing potential of thereducing agent used in the welding electrode would undoubtedly reducesome of the metal compounds in the same manner as the lithium compound.

Research carried out in this area indicated that the propensity ofelemental lithium to suppress nitrogen boil might be due to someproperty of lithium which it has in common with the other alkali metalsand not, as suggested in the Parks application, merely the fact thatlithium is lighter than nitrogen and tends therefore to displace it fromthe hot center of the welding arc.

Following this reasoning, compounds of mineral-type complexes containingpotassium and sodium as the alkali metal were developed and tested asagents to eliminate or substantially reduce the nitrogen boil. Testswith potassium and sodium as the nitrogen boilprevention agents weresuccessful, and on this basis, it is believed that the remaining alkalimetals, cesium and rubidium, would also be successful.

The present invention contemplates a new and improved welding electrodeand method wherein alkali metal compounds or mineral-type complexes arereduced to elemental alkali metal in the welding arc without requiringthe use of elemental calcium or other hygroscopic or hyperreactivereducing agents. Such alkali metal compounds or complexes shall bereferred to as composites in this specification and in the attachedclaims, it being understood that the term composites includes thevarious alkali metal ferrate, silicate, manganate, aluminate, etc.compounds, quasi-compounds and mineral-type complexes of the invention,as more fully describedhereinbelow. Some composites are believed to betrue chemical compounds and some are believed to exist with onlymineral-type bonding between molecules of constitutent compounds. It isnot critical to either understanding or practicing the invention to knowwhether, for example, the composite lithium ferrate exists as the truechemical compounds LiFeO and Li Fe O (as suggested by X-ray diffractionanalysis) or as a mineral-type complex of lithium oxide and iron oxidein fixed proportion, Li O-FeO (The oxygen content of the composite mayvary over a wide range without affecting the critical properties of thecomposites.)

In accordance with the invention, there is provided an alkali metalcomposite which is reduced in the welding arc to the elemental alkalimetal by aluminum, magnesium or other reducing agents. This alkali metalhelps to suppress the nitrogen boil and results in a weld metal of goodimpact strength and no porosity.

Acidic or amphoteric metal compounds which were found to combine withalkali metal compounds to form suitable composites are the oxides ofiron, manganese, silicon, aluminum, nickel titanium and cobalt, and itappears reasonable to assume that other metal compounds with similaracidic or amphoteric properties would also serve. Because they areexpensive, oxides of nickel and cobalt are less desirable from apractical, economic point of-view only. Aluminum oxide forms a compositewith alkali oxides which, although usable, appears to be more difficultto reduce to elemental metal in the arc than are the other metal oxidecomposites.

In accordance with one aspect of the invention therefore, there areprovided composites which comprise respectively, iron oxide, manganeseoxide, aluminum oxide, silicon dioxide, nickel oxide, titanium dioxideand cobalt oxide combined with one or more alkali metal compounds in acomposite which is non-hygroscopic relative to the corresponding alkalimetal compound. The composites are prepared by combining selected alkalimetal compounds and acidic or amphoteric metal compounds and heating themixture, either alone or with other components of the final electrodeflux material, at a temperature which will cause the alkali metal andacidic or amphoteric. metal compounds to combine one with the other toform the alkali metal composites of the invention.

More than one alkali metal compound and more than one acidic oramphoteric metal compound may be combined to form a composite inaccordance with the invention. While composites of the invention areless hygrosopic than the alkali metal compounds they contain, the degreeof hygroscopicity, i.e., the tendency to absorb moisture from the air,may vary as between the various composites of the invention. Somecomposites are quite resistant to moisture absorption and may be kept instorage for extended periods of time, while others must be used soonafter manufacture (or sealed in an air-tight packaging) in order toavoid excessive moisture pick-up.

In accordance with another aspect of the invention, therefore, moisturebarrier materials, namely, silicon dioxide, calcium oxide, aluminumoxide and magnesium oxide, are included in the composite composition.Sodium fluoride, lithium fluoride, calcium fluoride and barium fluoridealso are effective moisture barrier materials, and it appears reasonableto assume that the othr alkaline earth metal fluorides could also serveas moisture barrier materials. (The alkaline earth metals are beryllium,magnesium, calcium, strontium, barium and radium. Radium fluoride is, ofcourse, not suitable from a practical point of view, being radioactive.)These materials enhance the ability of the alkali metal composites toresist absorption of moisture from the air.

For example, lithium composites are prepared by mixing a lithiumcompound, (preferably lithium carbonate) with iron oxide, along withsilicon dioxide and other ingredients, as set forth in detailhereinbelow. The mixture is heated at high temperatures, preferablybetween about 1650F and 1850F., to form a mixture containing lithiumoxide (probably in the composite Li O'FeO with the remaining ingredientsin solid solution.

The proportion in which Li O and SiO are present in the finished fluxmaterial is important from a practical point of view, because mixtureswhich are too low in the proportion of lithium to silicon introduce toomuch silicon into the weld metal if sufficient lithium is provided tosuppress the nitrogen boil. (It should be noted that in this regard thesilicon dioxide is reduced to its elemental metal along with the lithiumcomposite metals by the aluminum or other deoxidizer present.) On theother hand, if the proportion of lithium to silicon dioxide is too high,the flux material will be unduly sensitive to moisture pick-upnotwithstanding the fact that the lithium oxide is bound up in thelithium ferrate composite.

Magnesium oxide, while it usually tends to aggravate the moistureabsorption probelms, likewise usually makes it easier to reduce thealkali metal composite to elementary alkali metal in the arc. Calciumoxide is, as mentioned above, a moisture barrier material and in generalhas the reverse effect on the moistureabsorption and ease-of-reductionof the composite to alkali metal. That is, calcium oxide usually tendsto abate the moisture-absorption problem but makes the composite moredifficult to reduce. Consequently, these two compounds (magnesium oxideand calcium oxide) may be combined to obtain desired chemical andphysical properties of the composite. Accordingly, in a limited aspectof the invention, magnesium oxide and calcium oxide, together withaluminum oxide, are used in conjunction with alkali metal oxide compoundto control both moisture pick-up and ease of reduction to elementaryalkali metal of the alkali metal oxide in the composite.

It is therefore a principle object of the invention to provide a weldingelectrode which is resistant to moisture absorption and gives anon-porous weld bead of high impact strength and good yield, tensile andelongation characteristics by releasing elemental alkali metal in thewelding arc without requiring metallic calcium or other hyperractivereducing agents, thereby substantially reducing or eliminating thenitrogen boil in the weld metal without the addition of excessivequantities of deoxidizers in the weld metal.

It is another object of the invention to provide an electric weldingelectrode containing alkali metal composites, preferably of lithium,sodium and potassium, (although rubidium and cesium are not excluded)which are reducible to elemental alkali metals in the arc, which do notrequire the presence of elemental calcium-containing reducing agents inthe flux, and which are not unduly hygroscopic.

Other objects and advantages of the invention will become apparent inthe following detailed description of the preferred embodiments thereofwhich comprise a hollow tubular electrode containing a flux whichincludes a alkali metal composites in accordance with the invention.

The alkali metal composites of the invention may be prepared incombination with at least some of the other ingredients which willconstitute the finished flux material, or with their precursors. Thatis, the alkali metal compound and the acidic or amphoteric metalcompound and any moisture barrier materials may be combined withslagging agents which form a suitable slag in the welding operation, andwith alloying agents which enter the weld metal and impart desiredmetallurgical characteristics thereto, or with the precursors of theforegoing. These ingredients may be combined and the entire mixtureheated to form a constituent of the flux material. For example, calciumcarbonate,'a precursor, may be added to the mixture, and will bedecomposed iin the heating step to the moisture barrier material calciumoxide.

Some of the ingredients may perform dual functions. The reducing agentsor a portion thereof serve to reduce the alkali metal composite toelemental alkali metal in addition to serving as a deoxidizer. Themoisture barrier material SiO or a portion therof, is reduced to siliconand alloys with the Weld metal, while CaO, also a moisture barriermaterial, enters the slag system as a useful component thereof.

At this point it should be noted that the term steel shell as used inthe specification and claims refers to the steel welding electrode,whether in the form of a shell or a rod. In all cases, percent of totalelectrode weight or similar terms refer to the weight percent of thetotal combined weight of steel shell and other electrode ingredients.

The following Example I shows the preparation of a lithium ferratecomposite in accordance with the invention.

(in all the Examples mill scale is described simply as iron oxides sinceits composition varies depending on the conditions under which it wasproduced and since it is not uniform, often including elemental ironparticles with surface oxides.)

EXAMPLE I A mixture of the following is prepared:

Wt.% Lithium carbonate (Li,CO;,) 33.5 Mill scale (iron oxides) 66.5

The mixture is heated in a kiln having a maximum temperature of l850F,with a residence time in th kiln of 1 hour. The resulting compositecontains:

Wt. Lithium oxide Li,o) 15.8 iron oxide (Fe,0,) 84.2

EXAMPLE II A mixture of the following is prepared:

. Wt. Lithium carbonate (Li,CO;,) 25.5 Mill scale (iron oxides) 45.2Silicon dioxide (SiO 10.4 Calcium carbonate (CaCO 18.9

The mixture is heated in a kiln having a maximum temperature of 1850F,with a residence time in the kiln of one hour. The resulting compositecontains:

Lithium oxide (Li o) l3.6 Silicon dioxide (SiO 13.6 Calcium oxide (CaO)l3.6 iron oxide (Fe O 59.2

(The average value of x ranges between about 1.6 and 3.0 inclusively.)

EXAMPLE II-A The amounts of Li CO mill scale, Si and CaCO are varied, soas togive a composite, after heating, of the following preferred range:

Wt. Lithium oxide (Li,O) l0 l8 Silicon dioxide (SiO,) l0 28 Calciumoxide (CaO) 0 20 iron oxide (Fe Q Remainder (The average value of xranges between about 1.6 and 3.0, inclusively.)

X-ray diffration analysis of the lithium ferrate composite shows stronglines for Li O'FeO. However, oxygen analysis indicates that thecomposite can vary over a wide range of oxygen levels without beingaffected adversely in its sensitivity to moisture pick-up. Lines for theindividual components are absent, indicating that the silicon dioxideand the calcium oxide are chemically involved with the lithium ferratecomposite Li O'Fe O As hereinabove stated, oxides besides iron oxide maybe employed. Manganese oxide and nickel oxide are exemplified inExamples ill and IV, respectively. Titanium dioxide may be used as wellas silicon dioxide, aluminum oxideand cobalt oxide.

Similarly, satisfactory results were obtained using sodium in place oflithium, as shown in EXAMPLE V.

EXAMPLES III A mixture of the following is prepared:

Lithium carbonate Li,co, 25.5 Mill scale (iron oxides) 39.6 Silicondioxide sio, 10.4 Calcium carbonate (CaC0,) 18.9 5.6

Manganese ore (approx. 40% MnO)- This mixture is heated in a kilm havinga maximum temperature of l,850F. with a residence time in the kiln of 1hour. The resulting composite contains:

Wt.% Lithium oxide (Li O) 13.6 Silicon dioxide (SiO 13.6 Calcium oxide(CaO) 13.6 iron oxide (F6201) 52.0 Manganese oxide (Mn,O 7.2

EXAMPLES IV A mixture of the following is prepared:

Wt.% Lithium carbonate taco 25.5 Mill scale (iron oxides) 34.0 Silicondioxide (SiO 10.4 Calcium carbonate (CaCO l8l9 Manganese ore 5.6 Nickelsinter (Ni0+Ni) 5.6

The mixture is heated in a kiln having a maximum temperature of 1,850F,with a residence time in the kiln of 1 hour. The resulting compositecontains:

Wt.% Lithium oxide (Li-,0) 13.6 Silicon Dioxide (siO |3.6 Calcium oxide(CaO) 13.6

iron oxide (Fe,0,) 4 Manganese oxide (Mn O,) Nickel oxide (N 0,)

This material is a lithium ferrate, lithium nickelate, lithium manganatecomposite, including silicon dioxide and calcium oxide, as moisturebarrier components, probably in a single crystal structure with themanga- 5 nese and nickel substituting for the iron in a random manner.(The average value of x ranges between about 1.6 and 3.0, inclusively.)

EXAMPLE V A mixture of the following is prepared:

The mixture is heated at 2,400F in a suitable container until themixture melts. The resulting composite material contains:

' Wt.% Sodium oxide (Na O) 16.7 Barium fluoride (BaF 16.5 Aluminum oxide(A1 29.5 Calcium oxide (CaO) 13.4 Silicon dioxide (SiO,) 23.9

EXAMPLE V-A Theamount of sodium carbonate, barium fluoride, aluminumoxide, calcium carbonate and silicon dioxide are varied so as to give acomposite, after melting, of the following preferred range:

Wt. Sodium oxide 15 38 Barium fluoride 0 20 Aluminum oxide 0 34 Calciumoxide 0 l Silicon dioxide Remainder The above material contains Si0 andN21 O and thus may be said to resemble a sodium glass. However, asidefrom the fact that the Na O and A1 0 are bound in a sodium aluminatecomposite, the finished material preferably has a silica contentappreciably lower than that of glass. Glasses generally contain at least60 percent silicon dioxide, and the lowest silica content glass, flintglass, contains at least about 45 percent silicon dioxide while thematerial prepared in accordance with the invention generally containsless than about 45 percent silicon dioxide and preferably not more thanabout 25 percent silicon dioxide.

Potassium may also be used as a substitute for lithium in accordancewith the invention. A potassium-silica composite analogous to thesodium-silica composite described in Example V may be used. (In allcases, the nomenclature used to describe the composite is arbitrary,e.g., the potassium-silica composite of Example V could also bedescribed as a sodium aluminate, sodium calcia, etc. composite.) Thesilica (silicon dioxide) and barium fluoride of Example V serve asmoisture barrier components.

The flux composition provided in the inner core of or as a coating on atubular electrode generally comprises about 20 percent of the totalelectrode weight. That is,

the steel shell normally comprises 80% of the electrode weight with theflux core filling or coating providing the remainder. The composition ofthe steel shell is normally 0.05 to 0.07 percent carbon, about 0.50percent manganese with the balance being iron. Broadly, the steel shellwill comprise about 70 percent to about 90 percent of the totalelectrode weight. Example VI shows a preferred electrode compositionincluding a lithium ferrate composite in accordance with the invention.Other alkali metal composites of the invention may be directlysubstituted in Example VI for the lithium composition shown.

EXAMPLE v1 Wt. of Electrode Preferred Preferred Flux Amount RangeAluminum 2.4 2.0-2.8 Magnesium 2.2 1.8-2.6 Calcium fluoride 2.01.75-2.25 Barium fluoride 4.0 3.5-4.5

Sodium fluoride 0.3 0.2-0.4

Lithium composite material of Example II 8.0 7.0-9.0 Manganese 0.40.2-0.6 Carbon I 0.55 0.035-0.075 Potassium silicofluoride 0.1 0.0-0.2

Steel Shell 80.55 79-82 With reference to Example VI above, and ExamplesVII and VIII following, the aluminum, manganese and carbon alloy withthe weld metal and are important in imparting desirable metallurgicalproperties to the weld metal. Alkali metal composites of the generalformula M O-Fe O M OSiO M O'COO, M O-NiO, M O-M- n O M O-Al o and MO-TiO (where x may vary from 0.8 to 1.5, inclusively, and M is an alkalimetal) are among those contemplated by the invention and may singly orin any combination be directly substituted, for example, for the lithiumcomposite of Example II in the formula of Example VII. Further, thecomposites may include moisture barrier materials in combination withthe other components. The composite materials from Examples II and V arehighly oxidizing. The other components of the fluxes of the examples areused in the known manner as slagging agents to adjust the slag volumeand slag freezing point as well as to modify the character of the arc.For example, potassium silico fluoride serves to quench the arc,increasing the voltage gradient across it and thereby increasing theamount of work done in the welding zone.

A preferred finished electrode composition containing a sodium aluminatecomposite is shown in Example VII.

EXAMPLE VII Wt. of Electrode In a preferred embodiment of the invention,a hollow tube electrode of low carbon steel is formed around a fluxmaterial containing alkali metal composites in accordance with theinvention, preferably, lithium, sodium or potassium composites. A hollowtube electrode is well suited to introduce, in accordance with oneaspect of the invention, the alkali metal composite into the weldingarc. The flux material also contains highly reactive reducing agents,preferably including aluminum, and may also contain iron powder toincrease its bulk, so that the flux material completely fills the hollowelectrode tube.

Example VIII shows another preferred finished electrode composition inaccordance with the invention.

Aluminum 2.0 2.8

Magnesium 1.2 1.8 Calcium fluoride l.5 2.0 Barium fluoride 7.0 9.5Sodium fluoride 0.1 0.4 Alkali metal composite 3.0 5.0 Nickel 0.3 0.9Carbon 0.035 0.075 Potassium silico fluoride 0.0 0.2 Steel Shell 79.0-82.0%

Example IX shows yet another preferred finished electrode composition inaccordance with the invention.

EXAMPLE IX Flux Wt. Aluminum l.7 2.2 Magnesium 1.2 1.8 Calcium fluoride1.0 2.0 Barium fluoride 7.0 9.5

Sodium fluoride 0.1 0.4 Nickel 0.3 0.9

Alkali metal composite 3.0 5.0 Carbon 0.035 0.075 Potassium silicofluoride 0.0 0.2

Steel Shell 79.0 82.0

While it is possible to introduce enough elemental a1- kali metal intothe electrode composition to preclude substantially any nitrogen entryinto the weld metal, it is generally satisfactory to introduce onlyenough alkali metal to suppress the nitrogen boil to the point where theamount of nitrogen retained in the weld metal is not more than about0.03 weight percent of the weld metal. An electrode content of about 0.2to 0.7 percent by weight of reducible lithium, of about 0.4 to 0.9percent by weight of reducible sodium and of about 0.5 to 1.0 percent byweight of reducible potassium, or pro-rata combinations of theforegoing, has been found sufficient under the conditions prevailing inthe welding arc to maintain nitrogen at a level not greater than about0.03 percent in the weld metal. By reducible metal, it is meant thatwhich is actually reduced from the composite to metallic form in thearc. If the reduction mechanism is not 100 percent efficient, i.e., ifsome of the alkali metal composite is not reduced, then the total amountused in the electrode must be increased proportionately. Generally, itis preferred, in accordance with one aspect of this invention, toprepare an electrode containing sufficient alkali metal compounds toprovide'from about 0.2 percent to about 1.0 percent by weight reduciblealkali metal in the electrode composition, which generally requiresabout 0.9 percent to about 10.0 percent by weight total alkali metalcomposite in the electrode composition. The amount of composite requireddepends, of course, upon the percent of composite weight due to alkalimetal, and the extent of reduction of composite to alkali metal.

' composite 0.2-l .0% Highly reactive deoxidizers 0.5-6.0% Total halidesl.5-l5.0% Total alloying agents 0.0-5.0% Other slagging materials0.0-5.0% Steel Shell 70.0-90.0% lron powder 0.0-15.0%

In general, the alkali metal composites of the invention suppressnitrogen boil and yield a non-porous weld metal with high impact valuesand good tensile and elongation characteristics.

A preferred electrode composition of the invention Wt. Defined BasisPreferred Range Alkali metal obtained from (Alkali metal obtained from acomposite refers to the stoichoimetric amount of lithium, sodium,potassium, rubidium, or cesium that would be extracted from therespective composite used if all the composite present is reduced. ifthe alkali metal percentage in the above table were described in termsof the corresponding alkali metal oxide composites, its value in theabove table would be approximately 5 to 10 times as great as the 0.2 to1.0 percent given for the alkali metal obtained. When the alkalicomposite is lithium ferrate or lithium manganate, the weight percent ofcomposite would be between about 3 percent to about 9 percent of thetotal electrode weight. Lithium titanate and lithium aluminatecomposites would have to be present in somewhat greater amounts becausethey are less efficiently reduced to elemental lithium. Naturally, asthe percentage of alkali metal present in any given composite decreases,more of the composite is required to provide the requisite amount ofalkali.)

Highly reactive deoxidizers are aluminum, calcium, cerium, zirconium,magnesium, titanium, lithium, silicon, and carbon in elemental form, asalloys, or as intermetallic compounds.

The lanthanide series elements (those elements of atomic number 57 to71) are also good deoxidizers but are generally quite expensive, andtherefore not preferred for use from a practical point of view. (Thelanthanide series elements are lanthanum, cerium, praseodymium,neodymium, promethium, samarium, europium, gadolinium, terbium,dysprosium, holmium, erbium, thulium, ytterbium, and lutecium.)

An aluminum deoxidizing system is strongly preferred and analuminummagnesium deoxidizing system is preferred because a residualamount of aluminum (about 0.5 percent and not more than 1.0 percent) inthe weld metal does not detract from its metallurgical properties, andthe oxides (or fluorides) of aluminum and magnesium formed by reductionof the alkali composite to elemental alkali metal enter the slag andgive it desirable properties. Halides refer to metallic halides,preferably alkali metal fluorides, alkaline earth fluorides, andaluminum fluorides, although other metallic halides are not excluded.

Total alloying agents or iron powder refer to components that becomepart of the weld metal in the welding process. These components areadded specifically to adjust the weld metal physical properties. Ironpowder also serves to make up a minimum amount of core filling tofacilitate loading and forming of the hollow rod electrode. I

Other slagging materials are oxides, silicates, carbonates, or mixturesthereof. The principal function of these materials is to adjust the slagcomposition, melting point, wetting action and arc action, or to adjustthe volume of slag.

Two or more of the alkali metal composites of the invention any any twoor more deoxidizers may, of course, be combined in any given electrode,along with other conventional ingredients.

It is important in accordance with the invention that the alkali metalcomposites of the invention are not formed in situ by the heat of thewelding arc,'but are prepared in advance and thenadded to the electrodematerial. That is to say, the acidic/amphoteric metal oxide and anymoisture barrier materials are reacted with the alkali compound atelevated temperatures, and the composite formed thereby is then blendedinto the electrode material. Formation of the composite attenuates thehygroscopic nature of the alkali compounds and permits the electrode tobe held in storage without undue moisture pick-up. The extent of thecomposite-forming reaction may be measured by the extent to which thehygroscopic nature of the alkali compound is attenuated. Hygroscopicityis the tendency of a material to absorb moisture from the air, and itshould be noted that formation of the composite attenuates thehydroscopic nature of the lithium compounds even when the compounddenominated moisture barrier materials are not present. The moisturebarrier materials have a pronounced effect in attenuating hygroscopicityeven when present in relatively small amounts.

The composite obtained in accordance with the invention is more stablein storage than its constituent materials, and yet is capable of beingreduced in the welding arc to elemental alkali metal. in preparing thecomposites, the mixture of materials is heated at a temperature highenough to form the composite (at least l,650F and preferably 1,850F) forsufficient length of time to form the composite (at least one hour oruntil the material melts). Lithium composites may be prepared by heatingthe mixture at between about 1,650F and l,850F, preferably at 1,850F,for up to 12 hours, preferably for 1 hour. Sodium composites may be pre-4 pared by heating the mixture of materials at a temperature of betweenabout 2,200F and about 2,600F, preferably at 2,400F until it melts.

The application of Parks filed concurrently herewith describesarrangements and methods for reducing lithium compounds in the heat ofthe arc to metallic lithium so that metallic lithium in the arc can actto exclude nitrogen. To avoid the problems of hygroscopicity, Parksemployed the more stable non-hygroscopic lithium compounds which in turnrequired a more active reducing agent such as calcium which in turn hadto be treated so as to reduce its hygroscopic tendencies.

The present invention has basically treated the less stable, morehygroscopic alkali metal compounds so as to substantially reduce theirhygrosopic tendencies by forming them into composites and then to usereducing agents which are sufficiently active to reduce these alkalimetal composites to the basic metal in the heat of the arc. By so doing,it has been discovered that even the heavy alkali metals will performthe same function as lithium, namely of excluding nitrogen from the arc.By heavy alkali metals is meant all of the alkali metals excludinglithium. Thus, if the hygroscopic tendencies of the heavy alkali metalcompounds can either be ignored or reduced by manufacturing theelectrode under very low humidity conditions and/or storing theelectrode until actual use under low humidity conditions, or using theelectrode immediately after manufacture, it is possible to use, inaccordance with the invention, the hygroscopic (non-composite) heavyalkali metal compounds in combina-tion with the reducing agentsufficiently active to reduce the alkali metal compound and produce freealkali metals in the arc.

The term sufficiently active is important. For example, some heavyalkali metal compounds are reduced by reducing agents which areincapable of reducing other heavy alkali metal compounds.

For example, aluminum and titanium are not sufficiently active reducingagents to reduce sodium, lithium, or potassium fluoride. For thisreason, examples 1-4, 8, 9 and 13 of Landis et al. US. Pat. No.2,909,778 are distinguishable from this phase of the present invention.Aluminum will, however, reduce heavy alkali silicofluoride.

For the heavy alkali metal fluorides as noncomposites, the most suitablereducing agents are aluminum, magnesium, calcium, carbon and thelanthanide series elements.

Among the various heavy alkali metal compounds the oxides, fluorides,silico fluorides and silicates are commonly available and may be used asthe heavy alkali metal compounds in accordance with the invention. Anexample of a welding electrode employing a potassium silico fluorideheavy alkali metal compound and aluminum reducing agent is as follows:

Wt. Magnesium l ll .5 Aluminum 2.5-3.5 Calcium fluoride 7.6-9.6Potassium silico fluoride 1.5-2.5 Mill scale (iron oxides) 4.5-7.5Manganese 0.2-0.6 Steel Shell 78.5-81.5

It will be apparent that upon reading and understanding of the above,many modifications and alterations of the described invention will occurto those skilled in the art. It is intended to include all suchmodifications and alterations, insofar as they fall within the spiritand scope of the disclosed invention, in the appended claims or theequivalents thereof.

What is claimed is:

1. An arc welding electrode comprising a steel shell in combination withflux material, said flux material containing as an essential ingredientthereof,

a. at least one alkali metal(s) in the form of alkali metalcomposite(s), said composite(s) comprising the reaction product of analkali metal oxide and an acidic or amphoteric metal compound, saidcomposite(s) being present in an amount sufficient to limit the amountof nitrogen retained in the weld metal to not more than about 0.03percent by weight of the weld metal, and

b. at least one reducing agent(s) capable of reducing said alkali metalcomposite(s) to elemental alkali metal in the welding arc and present inat least the stoichiometric amount necessary to so reduce all of saidalkali metal composite(s).

2. The electrode of claim 1 wherein said acidic or amphoteric metalcompounds are metal oxides.

3. The electrode of claim 2, wherein said metal oxides comprise one ormore metal oxides selected from the class consisting of oxides of iron,manganese, silicon, aluminum, nickel titanium and cobalt.

4. The electrode of claim 1, wherein said alkali metals comprise one ormore metals selected from the class consisting of lithium, sodium,potassium, cesium and rubidium.

5. The electrode of claim 1 wherein said alkali metal composites areselected from the class consisting of compounds of the general formula MO-Fe O M 0" sioz, M20'Al03, MgO'AlgOg, MZOCOO, MzO'NiO, M OMn O M OTiOand mixtures thereof, where M is the alkali metal and where x variesbetween 1.6 and 3.0.

6. The electrode of claim 1 wherein said alkali metal compositecomprises between about 0.9 percent and about 10 percent of the totalelectrode weight.

7. The electrode of claim 1 wherein said reducing agent comprisesbetween about 0.5 percent and about 6.0 percent of the total electrodeweight.

8. The electrode of claim 1 wherein said reducing agents comprise one ormore reducing agents selected from the class consisting of aluminum,magnesium, calcium, lithium, cerium, zirconium, silicon, titanium,carbon, and alloys or intermetallic compounds thereof.

9. The electrode of claim 1 wherein said reducing agents comprise oneor'more deoxidizers selected from the class consisting of aluminum,magnesium and alloys or intermetallic compounds thereof.

10. The electrode of claim 1 wherein said reducing agents comprise oneor more deoxidizers selected from the class consisting of the lanthanideseries elements.

11. The electrode of claim 1 wherein at least one of said compositesfurther include at least one moisture barrier material selected from theclass consisting of calcium oxide, silicon dioxide, magnesium oxide,aluminum oxide, lithium fluoride, sodium fluoride, barium fluoride andcalcium fluoride.

12. The electrode of claim 1 additionally including at least onemoisture barrier material selected from the class consisting of thealkaline earth metal fluorides.

13. The electrode of claim 1 wherein said composite is a lithiumcomposite and the lithium content (measured as elemental lithium) ofsaid electrode is between about 0.2 percent and about 0.7 percent of thetotal electrode weight and said reducing agent constitute between about0.5 percent to about 6.0 percent of the total electrode weight.

14. The electrode of claim 1 wherein said composite is Li O'Fe O saidreducing agent is selected from the class con-sisting of aluminum,magnesium and mixtures thereof, and x is between about 1.6 and 3.0.

1 5. The electrode of claim 1 having the following composition measuredas weight percent of the total electrode weight:

reducible alkali metal contained in said wherein the reducing agents areselected from the class consisting of aluminum, magnesium, calcium,cerium, zirconium, titanium, lithium, silicon, carbon, alloys orcompounds of any of the foregoing, and any mixtures thereof, and thehalides are selected from the class consisting of alkali metalfluorides, alkaline earth metal fluorides, aluminum fluoride, andmixtures thereof.

16. The welding electrode of claim 15 wherein the alkali metal compositeis a lithium composite and lith-- ium is present in said composite inamounts between about 0.2 percent and 1.0 percent of the total electrodeweight.

- l7. The welding electrode of claim 15 wherein the halides are selectedfrom the class consisting of calcium fluoride, barium fluoride andmixtures thereof.

18. The electrode of claim 1 wherein said alkali metal composite is alithium composite and said composite is present in an amount sufficientto provide at least about 0.2 weight percent (of the total electrodeweight) of reducible lithium in the electrode.

'19. The electrode of claim 1 wherein said alkali metal composite is asodium composite and said composite is present in an amount sufficientto provide at least about 0.4 weight percent (of the total electrodeweight) of reducible sodium in the electrode.

20. The welding electrode of claim 19 wherein sodium is present inamounts between about 0.4 to 0.9 percent of the total electrode weight.

21. The electrode of claim 1 wherein said alkali metal composite is apotassium composite and said composite is present in an amountsufficient to provide at least about 0.5 weight percent (of the totalelectrode weight) of reducible potassium in the electrode.

22. The electrode of claim 21 wherein potassium is present in saidcomposite in amounts between about 0.5 percent to about 1.0 percent ofthe total electrode weight.

23. The welding electrode of claim 1 wherein said one or more alkalimetals are selected from the class consisting of sodium, potassium,rubidium, and cesium, and said one or more reducing agents are selectedfrom the class consisting of aluminum, carbon, magnesium, calcium andthe lanthanide series elements.

24. An arc welding electrode comprising a steel shell in combinationwith flux material, said flux material containing as an essentialingredient thereof,

a. at least one heavy alkali metal compound, said heavy alkali metalcompound being present in an amount sufficient to limit the amount ofnitrogen retained in the weld metal to not more than about 0.03 percentby weight of the weld metal, and

b. in combination with the foregoing, at least one reducing agentsufficiently active to reduce said heavy alkali metal compounds to thecorresponding heavy alkali metal and present in at least thestoichiometric amount necessary to so reduce all of said heavy alkalimetal compound.

25. The electrode of claim 33 wherein said heavy al kali metal compoundsare selected from the class consisting of compounds of sodium,potassium, cesium or rubidium.

26. The electrode of claim 24 wherein the reducing agents are selectedfrom the class consisting of aluminum, magnesium, calcium, carbon, andthe lanthanide series elements.

27. The electrode of claim 26 wherein the heavy alkali metal compoundsinclude silico fluorides and the reducing agents include aluminum.

28. The electrode of claim 27 wherein the siliconfluorides includepotassium silico fluoride.

29. The electrode of claim 24 wherein said heavy alkali metal compoundis sodium and said compound is present in an amount sufficient toprovide. at least about 0.4 percent (of the total electrode weight) ofreducible sodium in the electrode.

30. The electrode of claim 29 wherein between about 0.4 and 0.9 percent(of the total electrode weight) of reducible sodium is present in theelectrode.-

31. The electrode of claim 29 wherein between about 0.5 and 1.0 percent(of the total electrode weight) of reducible potassium is present in theelectrode.

32. The electrode of claim 24 wherein said heavy alkali metal compoundis potassium and said compound is present in an amount sufficient toprovide at least about 0.5 percent (of the total electrode weight) ofreducible potassium in the electrode.

17 18 33. The electrode of claim 25 wherein the heavy althe followingapproximate range of composition in kali metal compounds are one or morecompounds seweight percent of total electrode weight: lected from theclass of oxides, fluorides, silico fluorides and silicates. Aluminum3-22 34. A welding electrode comprising a steel shell in 5 gfig' fii g 1:53 combination with flux material, said flux material hav- Bariumfluoride 7.0-9.5 ing the following approximate range of composition ina??? g--g-g 0 e weight percent of total electrode weight. Alkali metalcomposite Carbon 0.035-0.075 Aluminum 2.0-2.8 l 0 Potassium silicofluoride 0.0-0.2 Magnesium 1.2-1.8 Steel shell 79.0-82.0 Calciumfluoride 1.5-2.0 Barium fluoride 7.0-9.5 sodi m fluoride 0.l 0.4 38. Awelding electrode comprising a steel shell in ggtz g'gg-g combinationwith flux material, said electrode having Carbon 0.o35- o.07 5 l thefollowing approximate range of composition in Potassium silico fluoride0.0-0.2 Steel She" 79.042095 welght percent of total electrode weight.

Aluminum 2.0-2.8% 35. A welding electrode comprising a steel shell inMagnesium 1.8-2.6% combination with flux material, said electrode havinggalciumflfluoailde masgzhzgz arlum 1101'] e the following approximaterange of compositions ln Sodium fluoride 024.4% weight percent of thetotal electrode weight: Alkali metal composite 7.0-9.0% Manganese0.2-0.6% Magnesium Carbon 0.035-0.075% Aluminum 25 3.5 Potassiumslllcofluorlde 0.00.2% Calcium fluoride 7. 9.6 steel 79-0-8109?Potassium silico fluoride l.5-2.5 Mill scale (iron oxides) 4.5-7.5 h1k 1. l h Manganese w ereln sal a a1 meta composite comprises t e re-Steel shell 78.5-81.5

action product of an alkali metal oxide and an acidic or amphotericmetal compound.

39. The welding electrode of claim 38 wherein said kali metal compositeis a lithium composite.

40. The welding electrode of claim 39 wherein said lithium composite hasthe following range of composi- 36. A welding electrode comprising asteel shell in combination with flux material, said electrode having a]the following approximate range of compositions in weight percent of thetotal electrode weight:

Aluminum L60 240% tron in weight percent of the total lithium compositeMagnesium l.4o-2.-20% weight: Calcium fluoride 2.50-4.50% Sodiumcomposite l3.0-17.0% Carbon 0.03s-0.075% li F Slllcon dioxide 10.0-28.0%Manganese 02-06% C I 0 0 20 (W Steel rod 73.25-76.25% a Iron OxideRemainder. wherem Sald sodlum composite has the followmg 41. The weldingelectrode of claim 40 wherein said proximate range cmfposmm in weightpercent of 40 lithium composite material has the following approxithetotal composlte weight:

- mate composition in weight percent of the total com- Sodium oxidel5.0-38.0% Posite Weight Barium fluoride 0.0-20.0% Aluminum oxide0.0-34.0% m I16 Calcium f 5 Si lic d n dibliije 13.6 Slllcon dloxldeRemainder. I Calcium Oxide 3'6 37. A welding electrode comprising asteel shell in Iron oxide 59.2 combination with flux material, saidelectrode having UNITED STATES PATENT OFFICE CERTIFICATE OF CORRECTIONPatent No. 3,767,891 Dated October 23, 1973 Inventoflg) Robert ClaireHaverstraw, George Gideon Landis It is certified that error appears inthe above-identified patent and that said Letters Patent are herebycorrected as shown below:

Column 1, line 66, cancel "metallurgical" and insert "impact-"in lieuthereof.

Column 10, line 22, cancel "0.8 to 1.5" and insert --l.6 to 3.0- in lieuthereof.

Signed and sealed this 2nd day of April 1.97M.

(SEAL) Attest:

EDWARD MJ LETCHERJH. C. MARSHALL DANN Attesting Officer Commissioner ofPatents FORM PC4050 (169) uscoMM-Dc 60376-P69 Q;\

U.S. GOVERNMENT PRINTING OFFICE I 1969 0-366-334 q I UNITED sTATESPATENT OFFICE it i CERTIFICATE OF REQTWN Patent No." ,7 Dated October 231973 xfentOrQ) Robert Claire Haverstraw and George Gideon Landis It is'certified that error appears in the'above-identified patent and thatsaid Letters Patent are hereby corrected as show-nbelow:

I 7 Column 3, line 28, delete ffu lu u" and substitute 7 therefor alloysI I i i t Column 4, line 54, insert a comma between 'j'niokel' and'titanium I h Column 5', line 63, delete "probelms" and substitute v 1therefor problems i I Q A Column 6, line 37, delete "a'- therefrom.Column 6, line 53, delete "iin" and substitute therefor w Column 7, line19, delete "th" and substitute therefor the Column 8, line 20, delete"LIthium" and substitute therefor Lithium Column 8', line 29, delete"LIthium" and substitute therefor Lithium USCOMM-DC 60376-F'69 i u.ssovznumsm' PRINTING OFFICE: I989 o-ass-au FORM po-wsofflo-ss) Foampo-wso (in-s9) :Patent N 3,767,891

7 t V. I I; I Page 2 UNITED STATES-PATENT @FFICE I CERTIFit-A't of wDated October 23, 1973 tlnventoyfls) Robert Claire Haverstraw and GeorgeGideon Landis It is certified that error appears in the above-identifiedpatent and that said Letters Patent are hereby corrected as shown below:

, Column 16, the first line claim 25 delete :"33" and substitutetherefor 24 so that the dependency of claim 25 is changed from claim 33to claim 24.

Column 16, second line of claim 27, delete "silico flourides" andsubstitute therefor silicofluorides I Column 16, 1st and 2nd lines ofclaim 28, delete "silicon flourides" and substitute therefor---silicofluorides Column 16, second line of claim 28, delete silico Ifluoride" and substitute therefor silicofluoride Column 16, the firstline of claim 31, delete "31" and substitute therefor 32 delete "29" andsubstitute therefor I 31 and V Column 16, the first line of claim 32,delete "32" and substitute therefor 31 so that claim 32 is re numberedas claim 31 and claim 31 is re-numbered as claim 3 and is dependent fromre-numbered claim 31.

USCOMM-DC 5O376-P69 U.S. GOVERNMENT PRINTING OFFICE I969 0-356-334 Pegs'3 UNITED STATES PATENT UFFICE CERTIFICATE o to CNN fatemNo, 3,767,891Dated October 23, 1973 inventor) Robert Claire Haverstraw and GeorgeGideon Landis It: is certified that error appears in theabove-identified patent and that said Letters Patent are herebycorrected as shown below:

I Column 10, line ll, delete "0.55" and substitute therefor" 0.055 fColumn ll, line 6 and line 19,, delete "silico fluoride andfsubs'titutetherefor s ilicofluoride I I v v Column ll, line 58, delete "com-prises"and substitute therefor "comprises i I 7 Column 12-, line 54, delete thefirst occurrence of the word "any" and substitute therefor and -----u 7Column 13, line 56, delete "combina tion" and substitute therefor.combination r I Column 14, line 8, delete "silico fluorides" andsubstitute therefor silicofluorides 7 Column 14, lines 12 and 18, delete"silico fluoride" and substitute therefor silicofluoride I I 7 Column14, the last line in claim 3, insert a comma between. "nickel" and"titanium".

! FORM PO-.105O (10-69) I c USCOMMDC 6o376 P69 9 U.5, GOVERNMENTPRINTING OFFICE 2 I969 O-3$5334 Page A UNITED STATES PATENT OFFICECERTIFICATE or Pate'ht No. ,89 I Dated October 23, 1973 lnvehtofls)Robert Claire Haverstraw and George Gideon Landis It is certified thaterror appears in the above-identified patent and that said LettersPatent are hereby corrected as shown below:

Column 17, the third line of claim 33, delete 'E'silfico fluo" andsubstitute therefor silicoflu i Colunm 17, the 13th line of claim 34,and the 8th line of claim 35, delete silico fluoride" en d substitutetherefor fsilicofluoride Column 18, the 13th line of claim 37, delete'g'sili co fluoride" end eubstitute therefor silicofluoride ,Signed'endSealed this 8th day of October 1974.,

1 (SE'AL) Attesti .T MCCOY M. GIBSON 'JR. c. MARSHALL DANN j Attest-ingOfficer Commissioner of Patents FORM Po-ioso (10-69) i USCOMM-DC- e031s-pe Y U.5. GOVERNMENT PRINTING OFFICE 1969 0 666-334

2. The electrode of claim 1 wherein said acidic or amphoteric metalcompounds are metal oxides.
 3. The electrode of claim 2, wherein saidmetal oxides comprise one or more metal oxides selected from the classconsisting of oxides of iron, manganese, silicon, aluminum, nickel,titanium and cobalt.
 4. The electrode of claim 1, wherein said alkalimetals comprise one or more metals selected from the class consisting oflithium, sodium, potassium, cesium and rubidium.
 5. The electrode ofclaim 1 wherein said alkali metal composites are selected from the classconsisting of compounds of the general formula M2O.Fe2Ox, M2O.SiO2,M2O.Al2O3, M2O.CoO, m2O.NiO, M2O.Mn2Ox, M2O.TiO2, and mixtures thereof,where M is the alkali metal and where x varies between 1.6 and 3.0. 6.The electrode of claim 1 wherein said alkali metal composite comprisesbetween about 0.9 percent and about 10 percent of the total electrodeweight.
 7. The electrode of claim 1 wherein said reducing agentcomprises between about 0.5 percent and about 6.0 percent of the totalelectrode weight.
 8. The electrode of claim 1 wherein said reducingagents comprise one or more reducing agents selected from the classconsisting of aluminum, magnesium, calcium, lithium, cerium, zirconium,silicon, titanium, carbon, and alloys or intermetallic compoundsthereof.
 9. The electrode of claim 1 wherein said reducing agentscomprise one or more deoxidizers selected from the class consisting ofaluminum, magnesium and alloys or intermetallic compounds thereof. 10.The electrode of claim 1 wherein said reducing agents comprise one ormore deoxidizers selected from the class consisting of the lanthanideseries elements.
 11. The electrode of claim 1 wherein at least one ofsaid composites further include at least one moisture barrier materialselected from the class consisting of calcium oxide, silicon dioxide,magnesium oxide, aluminum oxide, lithium fluoride, sodium fluoride,barium fluoride and calcium fluoride.
 12. The electrode of claim 1additionally including at least one moisture barrier material selectedfrom the class consisting of the alkaline earth metal fluorides.
 13. Theelectrode of claim 1 wherein said composite is a lithium composite andthe lithium content (measured as elemental lithium) of said electrode isbetween about 0.2 percent and about 0.7 percent of the total electrodeweight and said reducing agent constitute between about 0.5 percent toabout 6.0 percent of the total electrode weight.
 14. The electrode ofclaim 1 wherein said composite is Li2O.Fe2Ox, said reducing agent isselected from the class con-sisting of aluminum, magnesium and mixturesthereof, and x is between about 1.6 and 3.0.
 15. The electrode of claim1 having the following composition measured as weight percent of thetotal electrode weight: reducible alkali metal con- tained in saidcomposite(s) 0.2-1.0 reducing agents 0.5-6.0 halides 1.5-15.0 ironpowder 0.0-15.0 steel shell 70.0-90.0 other slagging materials 0.0-5.0total alloying agents 0.0-5.0 wherein the reducing agents are selectedfrom the class consisting of aluminum, magnesium, calcium, cerium,zirconium, titanium, lithium, silicon, carbon, alloys or compounds ofany of the foregoing, and any mixtures thereof, and the halides areselected from the class consisting of alkali metal fluorides, alkalineearth metal fluorides, aluminum fluoride, and mixtures thereof.
 16. Thewelding electrode of claim 15 wherein the alkali metal composite is alithium composite and lithium is present in said composite in amountsbetween about 0.2 percent and 1.0 percent of the total electrode weight.17. The welding electrode of claim 15 wherein the halides are selectedfrom the class consisting of calcium fluoride, barium fluoride andmixtures thereof.
 18. The electrode of claim 1 wherein said alkali metalcomposite is a lithium composite and said composite is present in anamount sufficient to provide at least about 0.2 weight percent (of thetotal electrode weight) of reducible lithium in the electrode.
 19. Theelectrode of claim 1 wherein said alkali metal composite is a sodiumcomposite and said composite is present in an amount sufficient toprovide at least about 0.4 weight percent (of the total electrodeweight) of reducible sodium in the electrode.
 20. The welding electrodeof claim 19 wherein sodium is present in amounts between about 0.4 to0.9 percent of the total electrode weight.
 21. The electrode of claim 1wherein said alkali metal composite is a potassium composite and saidcomposite is present in an amount sufficient to provide at least about0.5 weight percent (of the total electrode weight) of reduciblepotassium in the electrode.
 22. The electrode of claim 21 whereinpotassium is present in said composite in amounts between about 0.5percent to about 1.0 percent of the total electrode weight.
 23. Thewelding electrode of claim 1 wherein said one or more alkali metals areselected from the class consisting of sodium, potassium, rubidium, andcesium, and said one or more reducing agents are selected from the classconsisting of aluminum, carbon, magnesium, calcium and the lanthanideseries elements.
 24. An arc welding electrode comprising a steel shellin combination with flux material, said flux material containing as anessential ingredient thereof, a. at least one heavy alkali metalcompound, said heavy alkali metal compound being present in an amountsufficient to limit the amount of nitrogen retained in the weld metal tonot more than about 0.03 percent by weight of the weld metal, and b. incombination with the foregoing, at least one reducing agent sufficientlyactive to reduce said heavy alkali metal compounds to the correspondingheavy alkali metal and present in at least the stoichiometric amountnecessary to so reduce all of said heavy alkali metal compound.
 25. Theelectrode of claim 33 wherein said heavy alkali metal compounds areselected from the class consisting of compounds of sodium, potassium,cesium or rubidium.
 26. The electrode of claim 24 wherein the reducingagents are selected from the class consisting of aluminum, magnesium,calcium, carbon, and the lanthanide series elements.
 27. The electrodeof claim 26 wherein the heavy alkali metal compounds include silicofluorides and the reducing agents include aluminum.
 28. The electrode ofclaim 27 wherein the silico fluorides include potassium silico fluoride.29. The electrode of claim 24 wherein said heavy aLkali metal compoundis sodium and said compound is present in an amount sufficient toprovide at least about 0.4 percent (of the total electrode weight) ofreducible sodium in the electrode.
 30. The electrode of claim 29 whereinbetween about 0.4 and 0.9 percent (of the total electrode weight) ofreducible sodium is present in the electrode.
 31. The electrode of claim29 wherein between about 0.5 and 1.0 percent (of the total electrodeweight) of reducible potassium is present in the electrode.
 32. Theelectrode of claim 24 wherein said heavy alkali metal compound ispotassium and said compound is present in an amount sufficient toprovide at least about 0.5 percent (of the total electrode weight) ofreducible potassium in the electrode.
 33. The electrode of claim 25wherein the heavy alkali metal compounds are one or more compoundsselected from the class of oxides, fluorides, silico fluorides andsilicates.
 34. A welding electrode comprising a steel shell incombination with flux material, said flux material having the followingapproximate range of composition in weight percent of total electrodeweight: Aluminum 2.0-2.8 Magnesium 1.2-1.8 Calcium fluoride 1.5-2.0Barium fluoride 7.0-9.5 Sodium fluoride 0.1-0.4 Alkali metal composite3.0-5.0 Nickel 0.3-0.9 Carbon 0.035-0.075 Potassium silico fluoride0.0-0.2 Steel shell 79.0-82.0%
 35. A welding electrode comprising asteel shell in combination with flux material, said electrode having thefollowing approximate range of compositions in weight percent of thetotal electrode weight: Magnesium 0.0-1.5 Aluminum 2.5-3.5 Calciumfluoride 7.6-9.6 Potassium silico fluoride 1.5-2.5 Mill scale (ironoxides) 4.5-7.5 Manganese 0.2-0.6 Steel shell 78.5-81.5
 36. A weldingelectrode comprising a steel shell in combination with flux material,said electrode having the following approximate range of compositions inweight percent of the total electrode weight: Aluminum 1.60-2.40%Magnesium 1.40-2.20% Calcium fluoride 2.50-4.50% Sodium composite13.0-17.0% Carbon 0.035-0.075% Manganese 0.2-0.6% Steel rod 73.25-76.25%wherein said sodium composite has the following approximate range ofcompositions in weight percent of the total composite weight: Sodiumoxide 15.0-38.0% Barium fluoride 0.0-20.0% Aluminum oxide 0.0-34.0%Calcium oxide 0.0-15.0% Silicon dioxide Remainder.
 37. A weldingelectrode comprising a steel shell in combination with flux material,said electrode having the following approximate range of composition inweight percent of total electrode weight: Aluminum 1.7-2.2 Magnesium1.2-1.8 Calcium fluoride 1.0-2.0 Barium fluoride 7.0-9.5 Sodium fluoride0.1-0.4 Nickel 0.3-0.9 Alkali metal composite 3.0-5.0 Carbon 0.035-0.075Potassium silico fluoride 0.0-0.2 Steel shell 79.0-82.0
 38. A weldingelectrode comprising a steel shell in combination with flux material,said electrode having the following approximate range of composition inweight percent of total electrode weight: Aluminum 2.0-2.8% Magnesium1.8-2.6% Calcium fluoride 1.75-2.25% Barium fluoride 3.5-4.5% Sodiumfluoride 0.2-0.4% Alkali metal composite 7.0-9.0% Manganese 0.2-0.6%Carbon 0.035-0.075% Potassium silicofluoride 0.0-0.2% Steel shell79.0-82.0% wherein said alkali metal composite comprises the reactionproduct of an alkali metal oxide and an acidic or amphoteric metalcompound.
 39. The welding electrode of claim 38 wherein said alkalimetal composite is a lithium composite.
 40. The welding electrode ofclaim 39 wherein said lithium composite has the following range ofcomposition in weight percent of the total lithium composite weight:Lithium oxide 10.0-18.0% Silicon dioxide 10.0-28.0% Calcium oxide0.0-20.0% Iron Oxide Remainder.
 41. The welding electrode of claim 40wherein said lithium composite material has the following approximatecomposition in weight percent of the total composite weight: Lithiumoxide 13.6 Silicon dioxide 13.6 Calcium oxide 13.6 Iron oxide 59.2